Back Pain and Superior Vena Cava Syndrome

Today's case involved a woman who presented with acute, severe back pain of around two days’ duration.  She was admitted and ultimately diagnosed with back pain on the basis of metastatic small cell lung cancer.  Superior vena cava syndrome was also diagnosed.

There were multiple learning points from our discussions today:

-Back pain is one of the most common emergency department complaints and can represent a spectrum of disease from benign and self-limited conditions, to life-threatening causes.  Part of the job of a physician is to differentiate these causes.  A safe approach is to examine for the presence of “red flags” that may suggest a more serious cause.  This ensures that pain is not attributed to “musculoskeletal” causes when there is reason to suspect something more sinister.  Red flags we talked about are: constitutional symptoms, history of cancer or immunocompromised, trauma to the affected area, neurologic complications such as weakness or bowel/bladder dysfunction, recent instrumentation or infection, etc.

-In the right clinical context (e.g. absent red flags) it may be reasonable to defer neuroimaging and see the patient in follow up.  The patient can be treated symptomatically with anti-inflammatory medication, analgesics and rest.

-The expertly-taken history revealed that the patient had some neck fullness.  This led us to a discussion about superior vena cava syndrome.  This process occurs when the SVC is obstructed intrinstically or extrisically by a variety of mechanisms.  The typical symptoms include facial flushing/plethora, upper extremity and facial edema, dyspnea, cough, stridor, and distended facial/neck/upper extremity veins.  Physical examination may reveal Pemberton’s sign which is facial edema/cyanosis with elevation of both upper extremities to compress the thoracic inlet.

-Mechanisms of SVC obstruction have changed over the years.  Infectious causes like syphilitic aortitis and tuberculosis used to predominate, but malignant causes now do.  Typical malignancies include lung cancers of the small and non-small cell variety, lymphomas, germ cell tumours, and mesothelioma.  Additionally, one has to consider endovascular causes like de novo or catheter-related thrombosis.

-The treatment of SVC syndrome follows the old adage of “treating the underlying cause.”  In malignant processes (especially lymphoma or thymoma) steroid therapy with dexamethasone is quite helpful.  Chemotherapy-sensitive tumours like small-cell lung cancer would be amenable to urgent chemotherapy.  The mainstay of treatment for most radiosensitive tumours would be urgent radiation therapy (it is one of the few radiation oncology emergencies).  Finally, endovascular stenting could be considered if refractory to these other treatments.

Further Reading:

Wilson, L. D., Detterbeck, F. C., & Yahalom, J. (2007). Superior vena cava syndrome with malignant causes. New England Journal of Medicine, 356(18), 1862-1869.